Secretary of Defense Clark Clifford was born on December 25, 1906, in Fort Scott, Kansas, and grew up in St. Louis, Missouri. He obtained a law degree in 1928 and practiced law in St. Louis, joining the Naval Reserve during World War II. He became assistant naval aide to President Truman in 1945. After the war, Truman appointed him general counsel, in which position he helped draft the legislation which created the Department of Defense in 1947.

In 1950, Clifford left the White House to establish a private practice, representing many large corporations and continuing to advise government officials. He was President-Elect Kennedy's liaison with the Eisenhower administration, and performed many special assignment duties for the Kennedy and Johnson administrations before he was appointed Secretary of Defense in 1968. When Clifford became Secretary of Defense, he supported US involvement in the Vietnam War, advising Johnson against a moratorium on bombing North Vietnam. Once he became Secretary of Defense, however, he publicly called for an end to American involvement in the war, backing Johnson's bombing halt in November of 1968. In 1969, he returned to private legal practice in Washington. Clifford was awarded the Presidential Medal of Freedom, the highest honor awarded to civilians.